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Hi, i simply cannot figure out how to complete this puzzle. Looked up some of the advanced techniques and managed to get x-wing to cross a few 5's out, but now i'm stuck again. Please help!

Hi,

Dutchnesss wrote:Hi, i simply cannot figure out how to complete this puzzle. Looked up some of the advanced techniques and managed to get x-wing to cross a few 5's out, but now i'm stuck again. Please help!

You could simplify the puzzle a little more by noticing the triple 147c4 and the quad 1578r2 which eliminates 7r2c9, and the puzzle ends with the singles.
Cordially
Robert

Code: Select all

*-------------------------------------------------*
| 9  125    7    | 1346  8     1245 | 345 35 3456 |
| 4 *158   *58   | 367-1 7-1  *15   | 9   2  367  |
| 3  25     6    | 47    247   9    | 8   1  457  |
|----------------+------------------+-------------|
| 8  34     234  | 147   1247  6    | 135 35 9    |
| 5  7      234  | 14    9     124  | 13  6  8    |
| 6  9      1    | 8     5     3    | 7   4  2    |
|----------------+------------------+-------------|
| 7  3468   348  | 5     1346  148  | 2   9  134  |
| 2  34568  3458 | 9     1346  148  | 345 7  1345 |
| 1  345    9    | 2     34    7    | 6   8  345  |
*-------------------------------------------------*

Another way is to note the naked triple (158) in the cells marked * which removes some 1's from Row2. r2c5 is then 7 and the puzzle solves with singles from there,

Leren

Look, where 3 and 6 are (*-ed cells)

Code: Select all

 +-------+-------+-------+
 | 9 . 7 | # 8 . | . . . |
 | 4 . . | # . . | 9 2 # |
 |*3 .*6 | . . 9 | 8 1 . |
 +-------+-------+-------+
 | 8 . . | . .*6 | . . 9 |
 | 5 7 . | . 9 . | . 6 8 |
 | 6 9 1 | 8 5*3 | 7 4 2 |
 +-------+-------+-------+
 | 7 . . | 5 ^ . | 2 9 . |
 | 2 . . | 9 ^ . | . 7 . |
 | 1 . 9 | 2 ^ 7 | 6 8 . |
 +-------+-------+-------+

In column 4 both 36 only can be in rows 12 (hidden pair).
Moreover in row 2 they cannot be in columns 236, and column 5 (because in box 8 3 and 6 must be in column 5). So you have another hidden pair 36 in r2c49.
This already solves with singles.

You also could eliminate 36 from r1c9, because this cell forms a unique rectangle with the pairs.